Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with a graphical user interface.

FIG. 2 is a second image thereof.

FIG. 3 is a third image thereof.

FIG. 4 is a fourth image thereof.

FIG. 5 is a fifth image thereof.

FIG. 6 is a sixth image thereof.

FIG. 7 is a seventh image thereof.

FIG. 8 is an eighth image thereof.

FIG. 9 is a ninth image thereof.

FIG. 10 is a tenth image thereof.

FIG. 11 is an eleventh image thereof; and,

FIG. 12 is a twelfth image thereof.

The outermost broken lines in each of the FIGS. show a display screen or portion thereof and do not form part of the claimed design. The other broken lines in the FIGS. showing small circles and numbers in the small circles illustrate portions of the graphical user interface that also do not form part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface, as shown and described. 